Automatic firearm



Jan., 6. 19257.

c. G. SWEBlLlUs AUTOMATI FIREARM Filed Jan. 17, 1922 Gu., W

Patented Jan. 6, 1925.

UNITED STATES isaiasi) PATENT OFFICE.

CARL GUSTAF SWEBILIUS, OF NEW HAVEN, CONNECTICUT, V.ASSIGrNOR TO THE MARLIN FIREARMS CORPORATION, OF NET HAVEN, CONNECTICUT, A CORPORATION OF DELAWARE. Y

AUTOMATIC FIREARM.

Application filed January 17, 1922. Serial No. 529,953.

To all 'whom t may concern: Y

Be it known that I, CARL GUSTAF Svi/'EBI- LIUs, a citizen of the United States,v residing at New Haven, in the county of New Haven and State of Connecticut, have invented a new and useful Improvement in Automatic Firearms, of which the following is a specification.

This invention relates to firearms and pertains more especially to automatic ries,

shotguns and pistols.

The gas pressure within the barrel of a gun immediately after the explosion is of the order of several thousand pounds to the square inch but decreases to a much lower pressure to the square inch as the projectile nears the muzzle of the barrel. The pressure of the gas immediately after the explosion is too great to be safely utilized to operate the mechanism of a gun, yet the subsequent decreased pressure is low enough to be safely used. In the operation of automatic guns, the breech mechanism is locked in its closed position during the period that vthe gas pressure is at its maximum power. After the gas pressure has decreased to a safe power, the gas pressure, exerted through suitable mechanism7 is then utilized to release the breech lock and reloading mechanism of the gun.

A previous method of locking the breech mechanism has been to provide an abutment slideway inclined to the axis of the barrel and a locking member adapted to be immovably clamped against said abutment by the high discharge gas pressure within the barrel transmitted to said locking member through the medium of the cartridge shell. The locking member is relieved from said clamping condition upon the decrease of gas pressure within the barrel to allow the locking member to move out of locking position under the influence of the lower gas pressure.

An object of my invention is the direct positive application of the high pressure of the gas within the barrel immediately after the explosion of a cartridge to means for lockingthe breech mechanism in its closed position, and the subsequent release of said locking means, upon the decrease of the gas pressure, to -allow the decreased gas pressure to operate the breech mechanism.

An additional object of the invention is to improve generally upon automatic guns by simplifying the structure and materially reducing the number of elements composing the guns. Y Y

These and other objects of the invention, which objects will be apparent from the following specification and accompanying drawings, are accomplished generally by providing ports in the barrel, forward of the chamber, which direct the gas against movable locking members arranged to bear against a portion of the breech mechanism. The clamping effect of these members when pressed against the portion of the breech mechanism by the high pressure of the gas in the barrel immediately after the explosion is suiicient to lock the breech mechanism in itsclosed position. The reduction of the gas pressure as the projectible passes along the barrel releases the lock effect, and the breech mechanism is then operated by the pressure of the gas bearing against it through the medium of the cartridge shell.

This invention will be better understood by having reference to the follo-wing specification and accompanying drawing wherein Fig. l is a longitudinal section of a gun disclosing an embodiment of the invention, the rear end of the receiver and the front end lof the barrel being broken oif; Fig. 2 is a section on the line 2-2 ofFig. 1 and Fig. 3 is a section on the line 3 3 of Fig. 1.

Into the front wall of the receiver 10 is screwed the barrel 11. Extending longitudinally of the barrel along its lower portion are the ribs 12. The breech bolt 13 is reciprocatively mounted in the receiver and has projecting forwardly therefrom the arms 14 which pass through the front wall of the receiver and are joined together at their forward ends by the cross member 15. Each of these arms 14 is provided with a groove 16 receiving one of the ribs 12. A rod 17 extends from the abutment 27 on the bottom plate 25, the abutment forming a part of the front wall of the receiver, and said rod is arranged between the arms lei. The forward end of the rod 17 extends through an aperture in the member 15. A helical spring 18 surrounds the rod 17 and its forward end its in'and abuts against the bottom of a socket in the memberl.

In the barrel, beginning just slightlyV in advance or the cartridge chamber, is a series or ports 19 which communicate with the sockets 20. These sockets are preferably symmetrically arranged with respect to and at an angle toA the vertical plane passing through the axis or the barrel, although they may be arranged in any other desired manner. In each socket is provided a plun1 ger 2l which, when in one position, projects beyond the surface or the barrel and its end engages a socket in one or the arms i4. The desi'On or the ends or the plungers and orV the sockets is such that when the plungers are forced into the sockets by the high gas pressure present inthe barrel im- 'mediately arterrthe explosion or the cartridge, the races or the plungers and or the sockets will stick or loch to each other so tightly as to prevent relative movement oi said races under the influence or the pressure eXerted rearwardly against Ythe breech bolt through the medium or the' cartridge shell.

A tiring pin 9.2 is reciprocatively mounted in the breech bolt l() and a hammer 23 is pivotally supported in the receiver to cooperate therewith. A trigger 2e in the bottom plate 25 serves to hold the hammer in cocked position. Extending through a slot in the bottom plate'is amagazine 26.

The operation or this gun4 is as oilows: lVhen the breech bolt is in its closed position as shownY in Fig. l, the plungers move, prererably by gravity, into the sockets in the arms le. Immediately ai'ter the explosion or the cartridge, the gas pressure in the barrel rises to an extremely high power. rl`he plungers 2l are forced into the sockets so strongly by reason or this pressure that the races orl the plungers and the soclrets stick or lock to each other sul'hciently to prevent the sliding or one on the other and this prevents rearward movement or the breech bolt notwithstanding the pressure exerted against it through the head or the cartridge case rollowing the explosion. As the bullet approaches the front end or the barrel, the gas pressure diminishes to a condition where the sticking or locking or the races or the plungers and sockets ceases. rlhe pressure exerted on the breech bolt through the head or the cartridge then causes the breech bolt to move rearwardly, the plungers being raised up out or the sockets by the sliding or their faces over the faces or the sockets. The design or the races or the plnngers andsoclrets may be varied to meet dierent conditions and it is within the contemplation or this invention that the ,races or the plungers may be smooth and contact with the surface or the arms, the sockets being dispensed with. The number or plungers may also be varied as desired to obtain the edect described.

It is, or course, obvious that various other modilications may be made in the structure and design or this type or gun without in any way departing from the spirit of the invention as set forth in the appended claims.

1What claim is:

l. in an automatic firearm, a receiver, a barrel carried thereby, a breech mechanism having a portion mounted in said receiver, and means for locking said breech mechanism in closed position, said means comprising a movable member forward or said receiver and bearing against a portion or said breech mechanism, said member. being subject directly to the gas pressure within the barrel, the locking action or said means being duesolely to the gas pressure.

2. In an automatic h'rearm, a receiver, a barrel carried thereby, a breech mechanism having a portion movably mounted in said receiver, a movable member forward of said receiver and adapted to bear against a portion or said breech mechanisni to lock said breech mechanism in closed position and means to subjectsaid member directly to the gas pressure within the barrel, the locking action or said Vmeans being due solely to the gas pressure.

ln an automatic lirearm, a receiver, a barrel carried thereby, a vbreech' mechanism having a portion movably mounted in said receiver, a movable member forward of said receiver and adapted to bear against a portion or said breech mechanism to lock said breech,mechanism in closed position anda port in said barrel to communicate the gas pressure within said barrel directly to said locking member, the locking action or said means being due solely to the gas pressure.

4. In an automatic lirearm, a receiver, a barrel carried thereby, a breech mechanism having a portion movably mounted in said receiver, and means forward or said receiver operated by the Ygas pressure within the barrel ror locking said breech mechanism in Vclosed position until the gas pressure has decreased to the requisite poweiarter the explosion of a cartridge, thelocking action or said means being due solely tothe gas pressure.

5. n an automatic lirearnji, a, receiver, a

barrel carried thereby, a breech bolt reciprocatively mounted in saidreceiver, an arm projecting forwardly trom said bolt, a port in said barrel and a plunger in' said port adapted to be i'orce'd against said arm by the initial highgas pressure within the',l barrel to loch said breech bolt in closed position until the gas pressure hasdecreased to the requisite extent, the locking action of said plunger beingdue solely to the gas pressure.

6. In an automatic' firearm, areceiver, a barrelcarried thereby, afbreech bolt reciprocatively moimtedV in said receiver, an arm projecting forwardly from 1said bolt, a socket in said arm, va port in said barreland a plunger in said port adapted to enter Asaid rie socket, the contacting surfaces of said plunger and socket being oblique to the axis of said plunger.

7. In an automatic firearm, a receiver, a barrel carried thereby, a breech bolt reciprocatively mounted in said receiver, an arm projecting forwardly from said bolt, a tongue and groove connection between said arm and barrel, a socket in said arm, a port in said barrel and a plunger in said port adapted to enter said socket, the contacting suritaces of said plunger and socket being oblique tc the axis of said plunger.

8. In an automatic firearm, a receiver, a barrel carried thereby and having a port, a breech mechanism having a portion mounted in said receiver, and a movable member in said port adapted to be forced against a portion of said breech mechanism by gas pressure within the barrel to lock said mechanism in closed position, the locking action of said means being due solely to the gas pressure.

9. In an automatic firearm, a receiver, a barrel' carried thereby and having a port, a breech mechanism having a portion mounted in said receiver, and means operated by the gas pressure within the barrel for locking said breech mechanism in closed position, said means comprising a plunger slidably mounted in said port, the locking action of said means being due solely to the gas pressure.

I0. In an automatic firearm, a receiver, a barrel carried thereby, a breech mechanism having a portion mounted in said receiver, and means for locking said breech mechanism in desired position, said locking means comprising a movable member carried by the barrel and subject to the gas pressure within the barrel to torce it into locking engagement with a portion of the breech mechanism, the locking action of said means being due solely to the gas pressure.

11. In an automatic firearm, a receiver, a barrel carried thereby, a breech mechanism having a portion mounted in said receiver, and means movable into engagement with a portion of said breech mechanism to lock it in closed position, said locking means being subjected directly to the pressure within the barrel through the medium of a short column of gas immediately after ring, the locking action of said means being due solely to the gas pressure.

l2. In an automatic firearm, a receiver, aV

barrel carried thereby, a breech mechanism having a portion mounted in said receiver, means movable by the gas pressure within the barrel for locking said breech mechanism in closed position, and a short passage for communicating the gas pressure to said locking means, the locking action of said means being due sole to the gas pressure.

18. In an automatic firearm, a receiver, a barrel carried thereby, a breech mechanism having a portion mounted in said receiver, andV means movable by gas pressure within the barrel for locking said breech mechanism in closed position, said means comprising a plunger mounted in a port in said barrel, the locking action of said means being due solely to the gas pressure.

14. In an automatic iirearm, a receiver, a barrel carried thereby, a breech mechanism having a portion mounted in said receiver, and means for locking said breech mechanism in closed position, said means comprising a movable member actuated through the medium of a short column of gas, the locking action of. said means being due solely to the gas pressure.

15. In an automatic firearm, a receiver, a barrel carried thereby, a breech mechanism having a portion mounted in said receiver, and means directly subject to gas pressure within said barrel for locking said breech mechanism instantaneously after the ring of a cartridge, the locking action of said means being due solely to the gas pressure..

16. In an automatic irearm, a receiver, a barrel carried thereby, a breech mechanism having a portion mounted in said receiver, and means instantly operated by the gas pressure within the barrel after firing for locking said breech mechanism in closed p0- sition, the locking action of said means being due solely to the gas pressure.

In witness whereof, I hereunto aiix my signature this 6th day of J an., 1922.

CARL GUSTAF SWEBILIUS. 

